Getting out my loupe and looking for the layered structure seen on traditional carved lacquer, as shown in the PDF linked to, it is barely detectable. Maybe 12 layers. There also appears to have been some sort of final thin layer applied, as the grooves show tiny crumbs, presumably not adequately brushed away after carving, glued in place under a thin shiny coating. Perhaps this final layer is why I didn't immediately see any layered structure. The lacquer itself appears to be thick and gooey, so something must have been added as a thickener.

https://www.realorrepro.com/article/Cinnabar

The material is soft enough to show scratches, and, as I mentioned, puts a red tint onto solvent-soaked wool.

The carving is nowhere as crisp and carefully done as the vases shown in the article, which, like the heart pendant, show a brass core, enamel, and cinnabar overlay. Some of these vases can be found with a cloisonne band around the middle. IIRC, the Beijing Enamel Company and the cinnabar factory were neighbors, under the umbrella of the Beijing Arts & Crafts Import & Export Corporation. They date from around the same decade as the pendant.